Khlong Damnoen Saduak (Thai: คลองดำเนินสะดวก, pronounced [kʰlɔ̄ːŋ dām.nɤ̄ːn sā.dùa̯k]) is a canal in western central Thailand.

It links the Tha Chin and Mae Klong rivers, and has a length of approximately 35 km.

At the mouth of the canal to the Mae Klong is the catholic Nativity of Our Lady Cathedral, the principal church of the Diocese of Ratchaburi.

In addition to connecting the Tha Chin and Mae Klong rivers, Khlong Damnoen Saduak is also bridged to Khlong Phasi Charoen as well, which is the route leading to the Chao Phraya River in Bangkok.

In the past, some vendors rowed boats from Damnoen Saduak or neighbouring districts to sell their goods at the pier in front of Wat Kanlayanamit in Bangkok's Thonburi side.